Increase in Intensity of Electrochemiluminescence from Cell Consisting of TiO2 Nanohole Array Film

Abstract

The increase in the intensity of electrochemiluminescnece (ECL) from cells consisting of titania nanohole array film (T-NHA-AL) is reported. The T-NHA-AL with a thin alumina insulation layer on the edge was prepared by an improved liquid-phase deposition method. The T-NHA-AL was sandwiched between two transparent conductive glasses (F-doped , FTO). The space between these two FTO substrates was filled with a solution of in propylene carbonate. The ECL from the cell was observed by applying ac bias on the FTO glass electrode. The ECL from the cell consisting of the T-NHA-AL was larger than that without T-NHA-AL (the cell with flat FTO glasses). In addition, the ECL intensity from the cell consisting of T-NHA-AL was higher than that consisting of alumina nanohole array (anodically oxidized porous alumina). The increase in the intensity of the ECL from the cell consisting of T-NHA-AL was explained by the electron injection from the large surface of the T-NHA-AL and the confinement of the luminescence species [Ru(I) and Ru(III)] in the restricted area of nanopores in the T-NHA-AL film. If a nanohole array film without the thin layer on the edge (T-NHA) was inserted between these two electrodes, short circuiting occurred through the T-NHA film. It is emphasized that the thin alumina insulation layer at the edge of the T-NHA-AL film is essential to realize an increase in ECL intensity.